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Front. Microbiol. | doi: 10.3389/fmicb.2018.03151

Red fluorescent Chlamydia trachomatis applied for live cell imaging and screening for antibacterial agent

Sergio A. Mojica1, Anna Eriksson1, Rohan A. Davis2, Wael Bahnan1,  Mikael Elofsson1 and  Åsa Gylfe1*
  • 1Department of Clinical Microbiology, Umeå University, Sweden
  • 2Griffith Institute for Drug Discovery,, Griffith University, Australia

In this study, we describe the application of a transformed Chlamydia trachomatis strain constitutively expressing the red fluorescent protein mCherry, to allow real-time monitoring of the infection cycle and screening for agents that block replication of C. trachomatis. The red fluorescent C. trachomatis strain was detected autonomously without antibody staining and was equally susceptible to doxycycline as the wild type strain. A high throughput-screening assay was developed using the transformed strain and automated fluorescence microscopy. The assay was used in a pilot screen of a 349 compound library containing natural products from Australian flora and fauna. Compounds with anti-chlamydial activity were tested for dose response and toxicity to host cells and two non-toxic compounds had 50 % effective concentration (EC50) values in low micromolar range. Natural products are valuable sources for drug discovery and the identified Chlamydia growth inhibition may be starting points for future drug development. Live cell imaging was used to visualize growth of the red fluorescent C. trachomatis strain over time. The screening assay reduced workload and reagents compared to an assay requiring immunostaining and could further be used to monitor the development of Chlamydia inclusions and anti-chlamydial effect in real time.

Keywords: Chlamydia trachomatis, high content screening, Natural Products, Antibacterial, Anti-chlamydial, Fluorescence-based screening, Australian biodiversity

Received: 01 Oct 2018; Accepted: 05 Dec 2018.

Edited by:

Jan Rupp, Universität zu Lübeck, Germany

Reviewed by:

Erika I. Lutter, Oklahoma State University, United States
Mirja Puolakkainen, University of Helsinki, Finland  

Copyright: © 2018 Mojica, Eriksson, Davis, Bahnan, Elofsson and Gylfe. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: MD, PhD. Åsa Gylfe, Umeå University, Department of Clinical Microbiology, Umeå, Sweden,